Commercial fishermen catch and process tons of fish a day. Many fishermen have complex, highly automated processing equipment that dresses the fish and produces numerous different commercial products for commercial retailers, such as restaurant chains or grocery stores. Such equipment is highly specialized to perform a specific task, such as cutting the heads and tails off, filleting, deboning and skinning, etc. One of the reasons such equipment must be tailored to specific tasks is the large variety of shapes and sizes of fish processed, including pollock, salmon, trout, sole, cod, etc.
To reduce overall processing costs and to improve quality, some commercial fishing vessels include processing equipment and freezers located directly on the ships. As the fish are caught, they are immediately processed and frozen, substantially improving the quality of the final product. This also allows the vessels to remain at sea for long periods of time without transporting the fish to a shore-based processing facility. Most of the processing equipment is large, complex, and expensive. It is difficult and expensive to remove the processing equipment from the vessel and replace it with new processing equipment.
Because of the expense associated with exchanging the processing equipment, including vessel down time, most commercial processing ships are intended to catch and process specific types of fish. As an example, the vessel may be fitted with processing equipment designed to process generally oval fish having a relatively thick cross section, such as pollock or salmon, or generally flat fish having a relatively thin cross section, such as sole. Due to the natural migration of fish, and various fishing laws, individual types of fish are caught and processed during limited times of the year. Therefore, vessels having equipment capable of processing only one type of fish sit idle during long periods of the year. If the processing equipment were available to process flat fish, such as sole, the vessels could be operated over a larger part of the year. This would, in turn, reduce the amount of down time and associated expense for the vessels.
One manufacturer of fish processing equipment is Baader GmbH & Co. KG, Lubeck, Germany ("Baader"). One of the many fish processing machines produced by Baader is the Baader 182. The Baader 182 is designed to process pollock and salmon-shaped fish and includes a conveyor having a plurality of fish holders mounted along the length of the conveyor. Each fish holder includes a recess configured to receive a pollock. While the processor is operating, a worker removes fish from a fish hopper located next to the conveyor and places an individual pollock in the recess of each fish holder. The conveyor subsequently moves the fish holders and pollock along the length of the conveyor into contact with rotating blades that cut both the head and the tail of the pollock off. The body of the pollock is then carried to additional equipment that cuts the pollock into fillets and removes the bones and skin.
The Baader 182 works well with fish having an oval cross section, such as pollock, but does not allow other types of fish to be processed. The Baader 182 is particularly unsuitable for processing fish with a relative flat cross section, such as sole. The fish holders used on the Baader 182 are not capable of holding such fish during processing. Nor can the Baader 182 remove the dorsal and anal fins of a flat fish.
Another of the many fish processing machines produced by Baader is the Baader 175 heading and filleting machine. The filleting section on the Baader 175 is designed to process flat fish, however, it does so at a slow rate that is not economically advantageous on modern processing ships which must process a large amount of fish in a short period of time to remain profitable. In addition, the filleting section on the Baader 175 has a difficult time processing flat fish having a relatively cross section, such as sole. Processing sole with the Baader 175 tends to result in a filleted fish that still includes portions of the backbone in the fish fillets produced by the machine, thus resulting in an unacceptable product. The Baader 175 is also prone to flat fish getting jammed in the fillet section. When jams occur, the entire machine must be shut down and disassembled to locate and correct the problem.
One goal of the present invention is to provide an apparatus and method to fillet flat fish at an increased line speed such that a large number of fish may be processed in a short period of time, thus increasing the profitability of the processing ship on which the equipment is used. Another goal of the present invention is to fillet a flat fish, such as sole, in a manner that removes the bones of the fish including substantially all of the backbone, thus producing a more acceptable commercial product.